Shimei Ryomou is an 18-year-old third-year student at Nanyo Academy, born September 3rd, and ranks among its elite "Big Four" fighters. Standing 160 cm tall with measurements of 85-58-86 cm, she has short dark blue hair (later transitioning to black), green eyes, and a distinctive mole on her left cheek. She typically wears fingerless gloves, combat boots, and either her school uniform or a blue French maid outfit in battle, her modified eyepatch constantly covering her left eye. Her combat expertise lies in submission techniques—throws, joint locks, and grapples—often augmented by handcuffs. She also wields chi-based energy blasts. Her signature move is "Ryoryuu Rakan Sanjuuroku Shiki: Tenchi Hakurogeki." As a B-rank fighter, she stands as one of Nanyo's strongest, second only to Saji Genpou among the Big Four. The eyepatch seals a dragon spirit within her left eye, releasing immense power that heals fatal wounds and elevates her strength to rival the Three Great Rulers. Unlike others, she coexists harmoniously with her dragon. Despite a traumatic past, she formed childhood bonds with Genpou Saji and Tokubou Teifu. Three years before the main events, she intervened in Gentoku Ryubi's dragon awakening, stopping Ryubi from self-harm and causing Ryubi's dragon to merge with her own left eye. This dragon later saved her life after a mortal wound from Teni. Ryomou became more reserved and stoic after Teifu's blinding and confinement to a wheelchair, though a softer side emerges, particularly in interactions with Hakufu Sonsaku. Her journey shifts from antagonist to key ally. Initially following Enjutsu's orders, she attacks Gakushuu and targets Hakufu, developing grudging respect after Hakufu defeats her. Ryofu Hosen humiliates, incapacitates, and sexually assaults her, igniting Ryomou's desire for revenge. In *Dragon Destiny*, she retrieves the Dragon Jade for Hakufu, awakening her dragon against Teni. She fights in the Battle of Chibi, aiding Sousou's defeat. Later, she trains with Hakufu under Master Chouko, learning to combine their strengths. In *Great Guardians* and *Xtreme Xecutor*, she works alongside Hakufu at a cosplay café and repeatedly protects her, confronting Ryofu again to shield her. Her relationships are complex: she harbors conflicted romantic feelings for the manipulative Saji, respects Koukin Shuuyu's intellect, and maintains loyal visits to Teifu. Her dynamic with Hakufu evolves from adversarial to protective; though annoyed by Hakufu's impulsiveness, she risks her life for her. Her rivalry with Ryofu transforms into mutual respect after Ryofu's death, leading Ryomou to honor Ryofu's final wish to safeguard Saji.